UNIVERSITY  OF   CALIFORNIA 

COLLEGE   OF   AGRICULTURE 

AGRICULTURAL    EXPERIMENT   STATION 

BERKELEY,    CALIFORNIA 


THE  VALUE  OF  ORANGE  PULP  FOR 
MILK  PRODUCTION 


W.  M.  REGAN  and  S.  W.  MEAD 


BULLETIN  427 

May,  1927 


UNIVERSITY  OF  CALIFORNIA  PRINTING  OFFICE 

BERKELEY,  CALIFORNIA 

1927 


THE  VALUE  OF  ORANGE  PULP  FOR  MILK 
PRODUCTION 

W.  M.  EEGANi  and  S.  W.  Mead2 


Faced  with  the  problem  of  disposing  of  thousands  of  tons  of  orange 
pulp,  the  annual  residue  from  their  manufacturing  processes,  the 
Exchange  Orange  Products  Company,  of  San  Dimas,  California, 
appealed  to  the  University  for  assistance  in  determining  the  value  of 
this  waste  as  a  feed  for  livestock.  The  results  of  investigations  begun 
for  this  purpose  by  the  Division  of  Animal  Husbandry  in  the  fall  of 
1924  show  that  dried  orange  pulp  is  a  satisfactory  feed  for  dairy 
cows,  having  a  value  for  milk  production  approximately  equivalent 
to  that  of  dried  beet  pulp,  and  that  neither  dried  nor  fresh  orange 
pulp  has  any  effect  upon  the  butterfat  tests. 

Orange  pulp  consists  of  the  rind,  flesh,  and  seeds  of  the  orange, 
and  a  small  amount  of  the  unrecovered  juice,  oils,  and  other  extracts. 
It  is  a  heavy  wet  mass  having  the  following  approximate  composition : 
Moisture  80.03  per  cent;  crude  protein  1.71  per  cent;  nitrogen  free 
extract  15.23  per  cent;  crude  fiber  1.61  per  cent;  ether  extract. 75 
per  cent;  and  ash  .67  per  cent. 

The  manufacture  of  orange  by-products  is  rapidly  increasing  with 
a  consequent  increase  in  residue  which  must  be  disposed  of  by  the 
factory.  During  the  year  ending  December  31,  1924,  the  Exchange 
Orange  Products  Company,  the  principal  manufacturers  of  these 
by-products  produced  more  than  9000  tons  of  the  wet  pulp  at  their 
San  Dimas  plant.  They  estimate  that  by  1930  the  volume  will  be 
50,000  tons.  The  disposal  of  this  residue  is,  therefore,  presenting 
yearly  a  more  serious  problem  to  the  manufacturers. 

The  first  extensive  attempt  to  utilize  fresh  orange  pulp  as  a  feed 
for  livestock  was  made  by  Mr.  Frank  Pellissier  on  his  dairy  ranch  near 
Whittier,  California,  in  the  summer  of  1922.  The  results  were  so  satis- 
factory that  the  demand  for  the  wet  pulp  rapidly  increased.  However, 
because  it  decomposes  so  quickly  and  has  such  a  high  moisture  con- 
tent, its  use  has  been  restricted  to  those  dairy  farms  within  trucking 
distance  of  the  factory.  These  are  able  to  use  only  a  small  portion 
of  the  total  amount. 


i  Associate  Professor  of  Animal  Husbandry,  Associate  Animal  Husbandman  in 
Experiment  Station. 

2  Assistant  Professor  of  Animal  Husbandry,  Assistant  Animal  Husbandman  in 
Experiment  Station. 


4  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

The  Exchange  Orange  Products  Company,  therefore,  conceived  the 
idea  of  dehydrating  the  fresh  pulp  and  marketing  it  as  a  livestock 
feed.  For  the  purpose  of  determining  its  value  as  a  feed  for  milk 
production,  the  first  experiment  described  below  was  undertaken. 


DRIED  ORANGE  PULP 

The  orange  pulp  used  in  this  trial  was  obtained  from  the  factory 
where  it  was  dried  in  temporary  equipment  to  approximately  12.5 
per  cent  moisture.  It  was  then  ground.  The  resulting  product  had 
very  much  the  appearance  of  fine  corn  meal. 

METHOD   OF   PROCEDURE 

Eight  cows  as  nearly  uniform  as  possible  in  weight,  stage  of  lacta- 
tion, and  gestation,  were  selected  from  the  University  herd.  They 
were  divided  into  two  lots.  Group  A  consisted  of  the  following  cows : 
Nos.  20,  108,  106,  and  327 ;  group  B,  of  Nos.  121,  326,  334,  and  357. 

Since  the  value  of  dried  beet  pulp  for  milk  production  is  known, (1) 
and  since  its  chemical  analysis  is  similar  to  that  of  dried  orange  pulp, 
the  former  was  used  in  this  trial  as  the  standard  of  comparison. 

The  feeding  trial  was  divided  into  two  periods  of  60  days  each. 
During  period  1  the  animals  in  group  A  received  alfalfa  hay  plus  a 
concentrate  mixture  consisting  of  equal  parts,  by  weight,  of  wheat 
bran  and  dried  orange  pulp.  Group  B,  during  the  same  time,  received 
alfalfa  hay  plus  a  concentrate  mixture  consisting  of  equal  parts,  by 
weight,  of  wheat  bran  and  dried  beet  pulp.  During  period  2,  group  A 
received  the  concentrate  mixture  containing  dried  beet  pulp  and 
group  B  that  containing  dried  orange  pulp. 

Every  ten  days  throughout  the  experiment  the  requirements  of 
each  animal  for  both  maintenance  and  milk  production  were  cal- 
culated, and  the  amounts  of  feed  adjusted.  An  attempt  was  made  to 
supply  the  alfalfa  hay  in  quantities  sufficient  to  satisfy  the  mainten- 
ance requirements  of  each  animal.  The  concentrate  mixture  fed  was 
calculated  to  supply  the  requirements  for  milk  production. 

Each  cow  was  milked  twice  daily,  her  milk  being  weighed  at  each 
milking.  A  daily  composite  sample  was  taken  and  its  percentage  of 
butterfat  determined.  Chemical  analyses  were  made  of  all  feeds  used, 
and  an  accurate  account  was  kept  of  the  feed  consumed  by  each  cow. 
To  ascertain  its  weight  at  the  beginning  of  the  experiment,  each 
animal  was  weighed  on  three  consecutive  days  and  the  average  taken. 
At  ten-day  intervals  throughout  the  experiment,  this  procedure  was 
repeated. 


BUL.  427]  VALUE   OF   ORANGE   PULP   FOR    MILK   PRODUCTION 


PRESENTATION     OF     DATA 

Period  1  lasted  from  December  18,  1924,  to  February  15,  1925,  and 
period  2,  from  February  16  to  April  16,  inclusive. 

To  determine  the  amount  of  feed  each  cow  should  receive,  the 
Armsby(2)  standard  for  maintenance  and  milk  production  was  used. 
The  body  weight  and  milk  and  fat  production  at  the  beginning  of 
each  ten-day  period  constituted  the  basis  for  calculating  the  individual 
daily  requirements.  The  energy  furnished  by  the  feed  was  ascertained 
by  the  Armsby  and  Fries (3)  method  for  computing  the  approximate 
net  energy  value  of  a  feeding  stuff. 


TABLE  1 

Composition,  Digestibility  and  Net  Energy  Values  of  Feeds  Used 


Feeding  stuff 


Wheat  bran  («) 

Period  1 

Wheat  bran 

Period  2 

Dried  beet  pulp 

(4),  Period  1 

Dried  beet  pulp 

Period  2 

Dried  orange 

pulp  (5), 

Period  1 

Dried  orange 

pulp,  Period  2 
Alfalfa  hay  (5) 

Both  periods... 


Water 

Crude  protein 

Nitrogen  free 
extract 

Crude  fiber 

Ether  extract 

Per  cent 

Per  cent 

Coeffi- 
cient of 
digesti- 
bility 

Per  cent 

Coeffi- 
cient of 
digesti- 
bility 

Per  cent 

Coeffi- 
cient of 
digesti- 
bility 

Per  cent 

Coeffi- 
cient of 
digesti- 
bility 

13.94 

15.73 

78.0 

52.06 

72.0 

9.50 

31.0 

2.98 

68.0 

9.93 

17.37 

78.0 

52.69 

72.0 

9.18 

31.0 

4.85 

68.0 

11.61 

8.52 

52.0 

58.30 

83.0 

18.31 

83.0 

0.86 

10.24 

8.86 

52.0 

57.13 

83.0 

20.17 

83.0 

0.97 

12.75 

7.56 

78.5 

66.81 

95.4 

7.87 

83.7 

1.68 

48.9 

11.44 

7.85 

78.5 

68.03 

95.4 

8.24 

83.7 

1.03 

48.9 

9.73 

15.49 

77.0 

38.46 

73.5 

25.66 

48.5 

1.85 

20.3 

Net 
energy 


Therms* 
50.91 
53.92 
74.57 
75.33 

89.84 
91.59 
36.92 


*  Value  per  100  pounds  for  ruminants,  calculated  according  to  Armsby  and  Fries. 

Table  1  gives  the  percentage  composition,  digestibility,  and  net 
energy  values  of  the  feeds  used  in  this  experiment.  The  net  energy 
received  by  each  animal  during  the  feeding  trial  was  derived  by  apply- 
ing the  coefficients  of  digestibility  to  chemical  analyses  made  at  this 
station.  The  coefficients  of  digestibility  for  wheat  bran  and  dried  beet 
pulp  were  taken  from  Henry  and  Morrison. (4)  Those  for  alfalfa  hay 
and  orange  pulp  were  determined  by  Mead  and  Guilbert.(5) 

The  accuracy  with  which  the  amount  of  feed  needed  by  each  cow 
was  determined  is  shown  in  table  2.  It  was  estimated  that  the  four 
cows  in  group  A  would  require  3404.3  therms  of  net  energy  during 
period  1.  The  feed  they  received  actually  furnished  3681.6  therms, 
thus   exceeding   the   requirements   by   277.2   therms   or   8   per  cent. 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


During  period  2,  they  received  an  excess  of  159.1  therms  of  net 
energy,  or  about  5  per  cent.  The  four  cows  in  group  B  received  dur- 
ing period  1,  134.4  fewer  therms  than  had  been  calculated  for  their 
requirements,  or  a  deficit  of  approximately  5  per  cent,  and  during 
period  2,  176.3  more  therms  than  had  been  calculated,  or  an  excess  of 
almost  7  per  cent. 

TABLE  2 

Feed  Consumed 
A  comparison  of  net  energy  required  and  that  received 


Period  1 

Period  2 

Cow  No. 

Pounds  of  feed 
eaten 

Therms  of  net 
energy 

Pounds  of  feed 
eaten 

Therms  of  net 
energy 

Alfalfa 
hay 

Concen- 
trates 

Re- 
quired 

Re- 
ceived 

Differ- 
ence 

Alfalfa 
hay 

Concen- 
trates 

Re- 
quired 

Re- 
ceived 

Differ- 
ence 

20 

537.3 

877.1 
970.5 
577.9 

0) 

789.8 
1237.4 
722.5 
927.6 

728.5 
1097.0 
720.7 
858.1 

754.2 
1194.6 
866.7 
866.1 

+  25.7 
+  97.6 
+146.0 
+    8.0 

596 .6 
879.0 
986.6 
544.4 

(2) 

676.0 
1024.0 
608.0 
842.1 

668.4 
915  5 

629.7 
772.9 

657.1 
986.2 
757.1 
745.2 

-  11.3 

108 

+  70.7 

106 

+127.4 

327 

-  27.7 

Group  A,  total... 

2962.8 

3677.3 

3404.3 

3681.6 

+277.3 

3006.6 

3150.1 

2986.5 

3145.6 

+159.1 

121 

590.8 
534.1 
561.2 

647.4 

(2) 

795.5 
522.1 
552.3 
1019.7 

752.5 
536.5 
580.6 
939.3 

717.2 
524.8 
553.7 
878.8 

-  35.3 

-  11  7 

-  26.9 

-  60.5 

586.5 
534.8 
624.9 
644.0 

0) 

710.3 
462.0 
417.1 
884.1 

697.3 
505.1 
479.0 
824.2 

733.3 
533.6 
534.2 
880.9 

+  36.0 

326 

+  28.5 

334 

+  55.2 

357 

+  56.7 

Group  B,  total... 

2333.5 

2889.6 

2808.9 

2674.5 

-134.4 

2390.2 

2473.5 

2505.6 

2682.0 

+176.4 

0)  Dried  orange  pulp  and  wheat  bran,  equal  parts  by  weight. 
(2)  Dried  beet  pulp  and  wheat  bran,  equal  parts  by  weight. 

The  nutrients  consumed  by  a  dairy  cow  in  excess  of  the  amount 
required  for  maintenance  result  in  either  production  of  milk  or 
increased  body  weight.  Therefore,  to  determine  the  efficiency  of 
dried  orange  pulp  as  compared  with  dried  beet  pulp  for  production, 
it  was  necessary  to  measure  the  effect  not  only  upon  milk  and  butterf  at 
production  but  upon  body  weights  as  well. 

The  total  average  weight  of  the  cows  in  group  A  was  5029  pounds 
during  period  1,  as  is  shown  in  table  3.  When  the  dried  beet  pulp  re- 
placed the  dried  orange  pulp  in  the  ration  during  period  2,  their  total 
average  body  weight  was  5049  pounds.  For  group  B,  the  total  average 
body  weight  during  period  2,  when  dried  orange  pulp  was  being  fed, 
was  4179  pounds ;  during  period  1,  this  weight  was  4151  pounds.  The 
difference  of  20  pounds  for  group  A  and  of  28  pounds  for  group  B, 
when  divided  among  the  individual  animals,  is  well  within  the  error 
of  weighing. 


BUL.  427]         VALUE   OF   ORANGE   PULP   FOR   MILK   PRODUCTION 

TABLE   3 

Individual  Body  Weights 

(Pounds) 


Group  A 

Group  B 

Weighing  dates 

Cow  No. 

Group 
total 

Cow  No. 

Group 

20 

108 

106 

327 

121 

326 

334 

357 

total 

December: 

16-17-18 

934 
933 

910 
928 
936 

922 
946 

1449 
1480 

1458 
1493 
1484 

1477 
1483 

1647 
1665 

1645 
1681 
1693 

1674 
1709 

1003 
965 

947 
952 
931 

910 
949 

5033 
5043 

4960 
5054 
5044 

4983 
5087 

1077 
1051 

1025 
1016 
1023 

1003 
1027 

917 
914 

893 
905 
891 

899 
918 

1085 
1053 

1023 
1043 
1043 

1073 
1089 

1172 
1172 

1161 
1147 
1147 

1138 
1155 

4251 

26-27-28 

4190 

January : 

7-  8-  9 

4102 

17-18-19 

4111 

27-28-29 

4104 

February: 

6-  7-  8 

4113 

16-17-18 

4189 

Average,  period  1 

930 

1475 

1673 

951 

5029 

1032 

905 

1058 

1156 

4151 

February: 

16-17-18 

946 
955 

959 
962 
965 

980 
971 

1483 

1478 

1451 
1430 
1422 

1396 
1403 

1709 
1690 

1725 
1701 
1709 

1735 
1737 

949 
931 

957 
926 
911 

942 
921 

5087 
5054 

5092 
5019 
5007 

5053 
5032 

1027 
1010 

1036 
988 
1020 

1037 
1033 

918 
907 

936 
937 
922 

928 
917 

1089 
1049 

1093 
1099 
1108 

1107 
1125 

1155 
1144 

1160 
1132 
1122 

1128 
1128 

4189 

26-27-28 

4110 

March: 

8-  9-10 

4225 

18-19-20 

4156 

28-29-30 

4172 

April: 

7-  8-  9 

4200 

17-18-19 

4203 

Average,  period  2 

963 

-1438 

1715 

934 

5049 

1022 

924 

1096 

1138 

4179 

TABLE  4 
Total  Milk  and  Butterfat  Production 


Cow  No. 

Milk  in 

pounds 

Percentage 

of 

decline 

Butterfat 

in  pounds 

Percentage 
of 

Period  1 

Period  2 

Period  1 

Period  2 

decline 

20 

1348 

2205 

995 

1596 

1091 
1598 
464 
1395 

19.1 
27.5 
53.4 
12.6 

59.2 
97.3 
29.7 
82.0 

49.5 
70.9 
16.5 
67.6 

16.4 

108 

27.1 

106 

44.4 

327 

17.6 

6144 

4548 

26.0 

268.2 

204.4 

23.8 

121 

1452 
539 
534 

1631 

1253 
470 
245 

1261 

13.7 
12.8 
54.1 
22.7 

57.9 
33.5 
35.0 
87.9 

51.1 

26.9 
16.4 
70.1 

11.7 

326 

19.7 

334 

53.1 

357 

20.3 

4156 

3229 

22.3 

214.3 

164.5 

23.2 

8 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


A  certain  normal  decline  in  milk  and  butterfat  is  expected  with 
advancing  lactation,  and  while  there  is  considerable  variation  in  the 
decline  in  production  among  the  individuals  within  the  groups,  as 
shown  by  table  4,  the  total  average  percentages  of  decline  for  both 
groups  are  practically  the  same.  Group  A,  on  dried  orange  pulp, 
produced  6144  pounds  of  milk;  on  dried  beet  pulp,  4548  pounds,  or 
26.0  per  cent  less  than  during  the  first  period.  Meanwhile,  group  B, 
on  dried  beet  pulp,  produced  4156  pounds  of  milk,  and  on  dried  orange 
pulp,  3229  pounds  representing  a  loss  of  22.3  per  cent.  The  declines 
in  butterfat  production  also  were  practically  the  same.  Group  A, 
when  on  beet  pulp,  gave  23.8  per  cent  less  butterfat  than  when  on 
dried  orange  pulp.  Group  B,  on  the  other  hand,  gave  23.2  per  cent 
less  butterfat  when  on  dried  orange  pulp  than  when  on  dried  beet 
pulp.    The  slight  difference  is  not  significant  in  either  case. 

Figure  1  shows  graphically  the  trend  of  milk  and  butterfat  produc- 
tion during  the  entire  experiment.  That  the  rates  of  decline  for  both 
groups  are  similar  in  periods  1  and  2  has  already  been  pointed  out. 

Since  the  amount  of  energy  furnished  by  the  feed  was  almost 
exactly  that  necessary  to  satisfy  the  requirements  for  maintenance  and 
production;  since  the  total  average  weights  of  the  groups  remained 
about  constant  throughout  the  experiment;  and  since  there  was  no 
significant  increase  or  decrease  in  milk  or  butterfat,  whether  dried 
orange  pulp  or  dried  beet  pulp  was  being  fed,  it  is  evident  that  the 
two  are  approximately  equal  in  value  as  a  feed  for  milk  production. 

This  observation  is  further  substantiated  by  the  results  of  a  25-day 
trial  conducted  with  five  grade  wether  sheep  to  determine  the  digestible 
composition  of  dried  orange  pulp  for  ruminants. (5) 


TABLE  5 
Digestibile  Nutrients  Contained  in  Various  Common  Feeds  Compared  with 

Dried  Orange  Pulp 


Feeding  stuff 


Total  dry 

matter  in 

100 

pounds 


Digestible  nutrients  in  100  pounds 


Crude 
protein 


Carbo- 
hydrates 


Fat 


Total" 


Dried  orange  pulp  (5) 

Barley  (4) 

Dried  beet  pulp  (4) 

Alfalfa  hay,  all  analyses  (4). 


Pounds 
87.5 
90.7 
91.8 
91.4 


Pounds 
6.0 
9.0 
4.6 
10.6 


Pounds 
70.4 


65.2 
39.0 


Pounds 
0.8 
1.6 
0.8 
0.9 


Pounds 
78.31 
79.40 
71.60 
51.60 


Total  includes  fat  X  the  factor  2.25. 


BUL.  427]  VALUE   OF    ORANGE   PULP   FOR    MILK   PRODUCTION  9 

According  to  the  figures  presented  in  table  5,  dried  orange  pulp 
compares  very  favorably  with  barley  in  total  digestible  nutrients, 
though  it  is  somewhat  lower  in  amount  of  digestible  crude  protein. 
Dried  beet  pulp  contains,  on  the  average,  4.6  per  cent  digestible  crude 
protein,  whereas,  the  orange  pulp  used  has  6.0  per  cent.  The  total 
digestible  nutrients  in  dried  orange  pulp  is  78.3  per  cent,  and  in  dried 
beet  pulp,  71.6  per  cent.  A  difference  in  feeding  value  as  small  as 
these  figures  indicate  could  not  be  detected  in  a  feeding  trial  for  milk 
production. 


O  L       o  C 


Period  1 •+- 

Period  2, 

■ H 

110 
130 

7 

\- 

%   3 

1 

2 

^  Butte r fat 

OA 

?ou 

p  / 

4 

-^ 

\/30 

\ 

Mi 

^ 

Ik 

^  90 
70 

"i     '     '     i  ~i — c 


i  -  r-  -i — i — i — i — i — r 


I     i     i  "~i     r 


0  10        20        30        40         JO       60         70        SO        90        100       110      120 

Number   of  Days 


k- 

—  Period  1  — 

-*\ 

Period  2 

— ^ 

140 

%/20 

6 

f 

■1< 

o 

\ 

, 

(jA 

?OL 

IP 

& 

\ 

A. 

Butter/at 

\ioo 

r 

60 

V 

V/M 

^ 

O 

1    1 

1       1 

1 

| 

| 

| 

"1       1      "1 

Fig. 


O         10        20       JO        40        JO        60         70        SO        90        /OO       110     120 
Number  of  Days 

1. — Trends  in  milk  and  butterfat  production  during  the  experiment. 
The  figures  used  are  five-day  averages. 


Dried  orange  pulp  is  not  a  highly  palatable  feed.  In  a  preliminary 
test,  it  was  refused  by  dairy  cows  when  unmixed  with  other  feeds. 
However,  during  the  feeding  experiment  as  much  as  eight  pounds  of 
dried  orange  pulp  were  consumed  daily  when  mixed  with  an  equal 
weight  of  wheat  bran. 


10 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


\l  1  1  1  1  1  1  II  1  II  1 

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hlumber  of  Days 

Wheat  Bran  and  Dried  Orange  Pulp 

Wheat  Bran  and  Dried^deet  Pulp 


Fig.  2. — Trends  in  butterfat  tests.     The  figures  used  are  five-day  averages. 


BUL.  427]    VALUE  OF  ORANGE  PULP  FOR  MILK  PRODUCTION  11 

Data  were  studied  to  determine  what  effect,  if  any,  the  feeding 
of  dried  orange  pulp  had  on  the  percentage  of  butterfat  in  the  milk. 
To  facilitate  graphic  presentation,  the  daily  butterfat  tests  were 
averaged  for  each  cow  so  as  to  cover  every  five  days  throughout  the 
experiment.  These  are  plotted  in  figure  2.  No  effect  is  evident  when 
the  curves  for  the  individual  cows  are  compared.  Cow  No.  20  in 
group  A  and  cow  No.  121  in  group  B  show  about  the  same  increase 
in  percentage  of  butterfat,  an  increase  that  is  ordinarily  expected  with 
advancing  lactation.  Though  the  averages  plotted  for  cow  No.  357  in 
group  B  are  irregular,  the  trend  of  her  tests  is  approximately  the  same 
as  that  of  cow  No.  108  in  group  A.  Cow  No.  106  in  group  A  and  cow 
No.  334  in  group  B  show  much  the  same  increase.  Cow  No.  327  in 
group  A  and  cow  No.  326  in  group  B  decreased  at  about  the  same  rate. 
While  an  increase  is  to  be  expected  with  advancing  lactation,  the 
reverse  is  not  uncommon  for  individual  cows  over  short  periods  of 
time. 

As  shown  in  table  4,  the  total  decline  in  butterfat  production  is 
23.8  per  cent  for  group  A  and  23.2  per  cent  for  group  B,  a  difference 
too  small  to  be  significant.  As  shown  in  figure  1,  the  curves  for 
butterfat  production  are  approximately  the  same  for  both  groups 
and  follow  very  closely  those  representing  the  trend  of  milk  produc- 
tion. Thus,  the  feeding  of  dried  orange  pulp  has  no  apparent  effect 
on  the  percentage  of  butterfat  in  the  milk. 


FRESH  ORANGE  PULP 

On  the  basis  of  dry  matter,  fresh  and  dried  orange  pulp  should 
have,  for  all  practical  purposes,  an  equivalent  feeding  value.  Had  it 
not  been  for  the  case  cited  below,  investigations  with  the  feeding  of 
the  fresh  pulp,  therefore,  would  have  been  deemed  unnecessary. 

In  1922,  Woll,  of  this  station,  studied  the  records  of  milk  and 
butterfat  production  of  cows  in  the  Pellissier  herd,  where  fresh  orange 
pulp  was  being  fed.  He  concluded  as  follows:  "There  is  a  strong 
indication  that  the  pulp  feeding  in  the  case  of  practically  all  of  the 
cows  resulted  in  a  marked  improvement  in  the  fat  content  of  the  milk, 
which  was  apparently  progressing  up  to  the  longest  period  of  the 
experimental  feeding,  viz.,  three  months.  The  increase  in  the  per- 
centage of  fat  in  the  case  of  individual  cows  was  frequently  as  much  as 
one-half  of  one  per  cent,  and  in  extreme  cases  over  one  per  cent. ' ' 

Since  there  is  no  feed  known(6)  which  will  affect  a  permanent 
increase  in  the  butterfat  test,  Woll's  observation,  if  substantiated, 


12 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


would  be  of  great  scientific  importance.  Though  the  trial  reported  in 
the  first  part  of  this  paper  showed  no  effect  on  the  butter  fat  test 
attributable  to  the  feeding  of  dried  orange  pulp,  the  possibility 
remained  that  the  factor  responsible  for  the  increase  in  test  noted  by 
Woll  had  been  destroyed  in  the  drying  process.  The  experiment 
described  in  the  following  pages  was  undertaken  for  the  purpose  of 
obtaining  definite  information  on  this  point. 

METHOD  OF  PROCEDURE 

An  attempt  was  made  to  carry  on  this  experiment  at  Davis,  but 
because  of  the  perishable  nature  of  fresh  orange  pulp,  it  became  neces- 
sary to  conduct  the  investigation  near  the  factory.  Mr.  E.  C.  Bennett, 
who  maintains  a  large  dairy  herd  at  Chino,  California,  kindly  offered 
a  portion  of  the  herd  for  the  trial.  Twenty-four  grade  cows  were 
selected  for  this  purpose.  All  of  these  were  in  rather  poor  flesh  but 
were  considerably  above  the  average  in  dairy  qualities.  They  were 
divided  into  groups,  A  and  B,  which  were  placed  in  separate  corrals. 
That  the  two  lots  were  balanced  is  shown  in  table  6.  The  average  body 
weight  for  group  A  was  825  pounds  and  for  group  B,  826  pounds. 
The  average  daily  milk  production  for  group  A  was  28.1  pounds, 
while  that  for  group  B  was  27.5  pounds.  Group  A's  average  test  was 
3.86  per  cent,  and  group  B's,  4.07  per  cent.  In  daily  butterfat  pro- 
duction both  groups  were  the  same. 


TABLE  6 

Initial  Records  of  Body  Weights  and  Production 


Group  A 

Group  B 

Cow  No. 

Weight 

Daily 

milk 

Butter 
fat 

Daily 
butterfat 

Cow  No. 

Weight 

Daily 

milk 

Butter 
fat 

Daily 

butterfat 

Pounds 

Pounds 

Per  cent 

Pounds 

Pounds 

Pounds 

Per  cent 

Pounds 

121 

725 

27.8 

4.1 

1.1 

96 

860 

29.1 

4.0 

1.2 

122 

720 

26.6 

3.9 

1.0 

123 

780 

32.1 

3.0 

1.0 

125 

865 

33.9 

3.4 

1.1 

124 

1020 

19.3 

4.8 

0.9 

126 

800 

25.7 

4.2 

1.1 

134 

795 

25.7 

3.7 

1.0 

128 

985 

39.1 

3.9 

1.5 

139 

770 

29.8 

4.9 

1.5 

129 

830 

24.2 

4  4 

1.1 

140 

670 

25.0 

4.7 

1.2 

131 

945 

40.7 

3.7 

1.5 

141 

825 

30.7 

3.6 

1.1 

132 

1035 

23.8 

4.1 

1.0 

142 

880 

25.0 

3.5 

0.9 

135 

555 

16.9 

4.8 

0.8 

144 

800 

34.7 

3.2 

1.1 

136 

1000 

35.4 

3.6 

1.3 

145 

700 

24.1 

5.1 

1.2 

143 

780 

28.8 

3.1 

0.9 

147 

970 

29.3 

5.0 

1.5 

172 

665 

14.0 

4.0 

0.6 

171 

840 

24.8 

4.0 

1.0 

Totals 

9905 

336.9 

13.0 

9910 

329.6 

13.6 

Average 

825 

28.1 

3.86 

1.1 

826 

27.5 

4.07 

1.1 

BUL.  427]         VALUE   OF   ORANGE   PULP   FOR   MILK   PRODUCTION  13 

The  basal  ration  consisted  of  alfalfa  hay  and  a  concentrate  mixture. 
The  latter,  which  contained  equal  parts  by  weight  of  ground  barley, 
ground  corn,  and  dried  beet  pulp  was  fed  according  to  production. 
In  addition,  each  cow  was  given  two  pounds  of  cottonseed  cake  daily. 
The  hay  which  was  fed  according  to  the  average  initial  body  weight, 
was  placed  daily  in  racks  to  which  all  cows  of  the  respective  groups 
had  free  access.  All  feeds  refused  were  weighed  and  deducted  from 
the  amount  given  in  order  to  arrive  at  the  total  consumption. 

The  feeding  trial  covered  a  period  of  110  daj^s.  During  the  first 
10  days,  both  groups  received  only  the  basal  ration.  During  the  next 
30  days,  each  cow  in  group  A  received  daily  20  pounds  of  fresh  orange 
pulp,  which  replaced  two  pounds  of  alfalfa  hay.  As  a  check,  group  B 
was  continued  on  the  basal  ration.  During  the  next  30  days,  the 
rations  were  reversed,  group  A  receiving  the  basal  ration  and  group  B 
the  fresh  orange  pulp.  During  the  following  30  days,  the  rations 
were  reversed  again.  During  the  last  10  days,  only  the  basal  ration 
was  fed. 

The  cows  were  milked  twice  daily.  A  competent  man  was  detailed 
to  oversee  the  feeding  and  handling  of  the  animals  and  to  do  all  weigh- 
ing, sampling,  testing,  and  recording  of  data,  The  milk  from  each 
cow  was  weighed  at  each  milking  and  a  daily  composite  sample  was 
taken  for  the  determination  of  the  percentage  of  butterfat.  The  cows 
were  weighed  every  30  days.  The  atmospheric  temperature  in  the 
milking  barn  was  recorded  each  morning  and  evening. 


PRESENTATION    OF    DATA 

For  the  purpose  of  presenting  the  data,  the  experiment  was  divided 
into  periods  of  10  days  each.  In  table  7  are  shown  the  body  weights, 
average  feed  consumed,  percentage  of  butterfat  in  the  milk,  and 
pounds  of  milk  and  butterfat  produced.  The  total  production  of  the 
two  groups  was  remarkably  uniform.  The  difference  between  the 
average  percentages  of  butterfat  for  the  total  experimental  period  was 
only  0.01. 

Because  of  the  irregular  fluctuations  that  are  normal  in  the  per- 
centage of  butterfat  found  from  day  to  day  in  the  milk  of  any  dairy 
cow,  a  study  of  the  daily  tests,  gives  very  little  indication  of  the 
general  trends. 

In  table  8  the  individual  tests  are  compiled  according  to  the  rations 
fed.  There  is  no  consistent  indication  that  the  feeding  of  fresh  orange 
pulp  has  any  effect  upon  the  percentage  of  fat  in  the  milk.     The 


14 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


tendency  to  increase  shown  in  the  table  can  logically  be  explained  by 
the  effect  of  advancing  lactation.  Variations  as  small  as  those  between 
the  successive  periods  will  usually  be  found  in  any  set  of  similar 
tests  regardless  of  the  ration  fed. 


TABLE  7 

Feed  Consumed,  Body  Weights  and  Production  Becords 

(Group  averages  by  ten-day  periods) 


Period 

Hay 

Concen- 
trates* 

Cotton- 
seed cake 

Orange 
pulp 

Body 

weight 

Total 
milk 

Butterfat 

Pounds   |    Pounds       Pounds    \    Pounds 

Pounds 

Pounds 

Per  cent  \    Pounds 

Group  A 


1   . 

190 
176 
170 
170 
190 
190 
190 
170 
170 
170 
190 

76 
69 
67 
70 
70 
70 
64 
61 
63 
63 
56 

20 
20 
20 
20 
20 
20 
20 
20 
20 
20 
10 

825 

270.9 
269.7 
254.5 
284.8 
272.6 
260.6 
246.7 
254.7 
255.9 
249.3 
226.0 

3.87 
3.90 
3.96 
3.89 
3.85 
4.05 
4.14 
4.40 
4.39 
4.65 
4.76 

10.5 

2  

157.9 
195.2 
199.7 

10  5 

3..  .. 

10.1 

4 

11.1 

5 

873 

10.5 

6 

10  5 

7 

10  2 

8 

187.8 
193.8 
197.3 

938 

11.2 

9     . 

11.2 

10  . 

11.6 

11..  . 

10.8 

2845.7 

4.16 

118.2 

Group  B 


1  .. 

190 
190 
190 
190 
170 
170 
170 
190 
190 
190 
190 

73 
71 
70 
71 
71 
71 
70 
67 
70 
70 
62 

19 
20 
20 
20 
20 
20 
20 
20 
20 
20 
10 

826 

274.3 
273.6 
278.3 
291.3 
284.8 
286.5 
277.5 
269.8 
256.0 
241.1 
237.3 

4.04 
3.82 
3.79 
3.74 
4.06 
4.34 
4.53 
4.28 
4.34 
4.42 
4.59 

11.1 

2 

10  5 

3 

10  6 

4 

10  9 

5 

139.5 
197.9 
176.2 

886 

11.6 

6 

12  4 

7            

12.6 

8          

944 

11.5 

9 

11  1 

10 

10  6 

11 

10.9 

2970.5 

4.17 

123.8 

*  Equal  parts  by  weight  of  ground  barley,  corn  meal  and  dried  beet  pulp. 

In  order  to  present  a  more  detailed  analysis  of  the  data,  the 
average  daily  butterfat  tests  for  each  group,  together  with  average 
daily  temperatures  in  the  milking  barn,  are  shown  graphically  in 
figure  3.  While  the  temperature  curve  has  many  fluctuations,  none 
of  these   correlate   definitely   with   the   variations   in   the   butterfat 


curves 


(7) 


BUL.  427]         VALUE   OF    ORANGE   PULP   FOR   MILK   PRODUCTION 


15 


TABLE   8 
The  Effect  of  Feeding  Fresh  Orange  Pulp  on  the  Fat  Percentage  in  Milk 


Group  A 

Group  B 

Cow 
No. 

Basal 
ration 
10  days 

Orange 

pulp 
30  days 

Basal 

ration 

30  days 

Orange 

pulp 
30  days 

Basal 
ration 
10  days 

Cow 

No. 

Basal 
ration 
10  days 

Basal 
ration 
30  days 

Orange 
pulp 
30  days 

Basal 
ration 
30  days 

Basal 
ration 
10  days 

121 

4.28 

4.37 

4.70 

5.40 

5.58 

96 

3.98 

3.51 

4.02 

4.18 

4  51 

122 

3.91 

4.30 

3.97 

4.48 

4.66 

123 

3.76 

3.75 

4.14 

4.21 

4.51 

125 

3.63 

3.69 

3.59 

3.85 

3.93 

124 

4.42 

4.37 

4.93 

4.99 

5.27 

126 

4.01 

3.98 

4.04 

4.44 

4.76 

134 

4  00 

3.91 

4.29 

4.66 

5.20 

128 

3.90 

4.00 

3.84 

4.28 

4.49 

139 

4.27 

3.92 

4.43 

4.49 

4.56 

129 

4.43 

4.45 

4.36 

4.89 

4.91 

140 

4.52 

4.50 

5.78 

5.73 

6.31 

131 

3.86 

4.09 

4.33 

4.88 

5.02 

141 

3.40 

3.08 

3.24 

3.23 

3.38 

132 

3.93 

3.81 

3.85 

4.22 

4.47 

142 

3.47 

3.56 

3.80 

3.83 

3.97 

135 

4.99 

5.42 

5.71 

6.10 

6.27 

144 

3.77 

3.42 

4.10 

3.87 

4.00 

136 

3.54 

3.44 

3.45 

3.77 

4.07 

145 

5.08 

4.62 

5.33 

5.43 

5.98 

143 

2.88 

2.80 

2.89 

3.07 

4.23 

147 

4.82 

4.72 

5.39 

5.13 

5.72 

172 

3.90 

3.73 

4.38 

5.20 

5.26 

171 

Group 
average 

3.50 

3.09 

3.66 

3.88 

3.99 

Group 
average 

3.94 

4.01 

4.09 

4.55 

4.80 

4.08 

3.87 

4.43 

4.47 

4.78 

90 

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Fig.  3. — Trends  in  butterfat  tests,  and  barn  temperatures. 


16  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


PALATABILITY 

Fresh  orange  pulp  seemed  to  be  relished  by  the  animals.  As  much 
as  twenty  pounds  a  day  were  consumed  for  a  period  of  thirty  days. 
The  palatability  is  considerably  better  than  that  of  dried  orange  pulp 
or  of  cull  oranges.  In  a  palatability  test,  incidental  to  the  experi- 
ments recorded  here,  difficulty  was  met  in  inducing  cows  to  consume 
more  than  four  or  five  pounds  of  cull  oranges  daily.  However,  after 
a  considerable  time,  the  cows  might  have  acquired  a  taste  for  them. 


CONCLUSIONS 

1.  Dried  orange  pulp  is  approximately  equivalent  to  dried  beet 
pulp  as  a  feed  for  milk  production. 

2.  One  hundred  pounds  of  dried  orange  pulp  contains  approxi- 
mately 78  pounds  of  total  digestible  nutrients. 

3.  Neither  fresh  nor  dried  orange  pulp  influenced  the  percentage 
of  fat  in  the  milk  produced. 

4.  While  fresh  orange  pulp  was  readily  eaten,  it  was  necessary  to 
mix  the  dried  pulp  with  a  more  palatable  feed. 


LITERATURE  CITED 

1  LlNDSEY,   J.  B. 

1913.     The  food  value  of  plain  and  molasses  beet  pulp.     Mass.  Agr.  Exp. 
Sta.  Bpt.  1913  (Part  1):  129-140. 

2  Armsbt,  Henry  Prentiss 

1917.     The  nutrition  of  farm  animals,     p.  711,  714.     Appendix  tables  I  and 
V.     The  MacMillan  Company,  New  York. 

3  Armsby,  Henry  Prentiss,  and  J.  August  Fries 

1915.  Net  energy  values  of  feeding  stuffs  for  cattle.    Jour.  Agr.  Eesearch 
3:486-487. 

4  Henry,  W.  A.,  and  F.  B.  Morrison 

1923.     Feeds    and    feeding.      18th    ed.,    p.    722-723.      Appendix    table    II. 
The  Henry-Morrison   Company,   Madison,  Wisconsin, 
s  Mead,  S.  W.,  and  H.  B.  Guilbert 

1926.     The   digestibility   of  certain  fruit  by-products   as   determined  for 
ruminants.     Part  I.  Dried  orange  pulp  and  raisin  pulp.     Cali- 
fornia Agr.  Exp.  Sta.  Bui.  409:1-11. 
e  McCandlish,  Andrew  C. 

1921.     The  use  of  cottonseed  meal  to  increase  the  percentage  of  fat  in 
milk.     Jour.  Dairy  Science,  4:310-333. 
7  Hays,  W.  P. 

1926.     The  effect  of  environmental  temperature  on  the  percentage  of  fat 
in  cow's  milk.     Jour.  Dairy  Science,  9:219-235. 

12m-6,'27 


